Paramilitary soldiers pour flocculants into a tank filled with water samples from a polluted river at a hydropower plant in Liuzhou, Guangxi Zhuang autonomous region January 28, 2012. Water and environmental authorities in south China's Guangxi Zhuang autonomous region are working to control cadmium pollution in the local river, while ruling out the possibility that water sources for Hong Kong and Macao have been contaminated, Xinhua News Agency reported. Flocculants can help suspended heavy metal particles aggregate, facilitating the easier dredging of pollutants. REUTERS/China Daily (CHINA - Tags: DISASTER ENVIRONMENT MILITARY) CHINA OUT. NO COMMERCIAL OR EDITORIAL SALES IN CHINA